


elevate the headstrong dead long halo

by warsfeil



Category: Shall We Date?: Obey Me!
Genre: F/M
Language: English
Status: In-Progress
Published: 2020-03-07
Updated: 2020-03-06
Packaged: 2021-03-01 01:20:08
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,854
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23046898
Author URL: https://archiveofourown.org/users/warsfeil/pseuds/warsfeil
Summary: “It’ssex,” Asmodeus says, finally. “You can sleep with a demon to complete forming a pact. It’s one of my favorite ways, in fact, but do you mean that Mammonhasn’tfinished forming one with you, in that case?”
Relationships: Main Character/Mammon (Shall We Date?: Obey Me!)
Comments: 14
Kudos: 163





	elevate the headstrong dead long halo

**Author's Note:**

> i went, "what if yuki formed pacts with the demons by sleeping together?" and then i decided: yes, writing this is definitely a sane thing to do, and i will do it, so Here We Go Y'all

Yuki does not habitually make pacts with demons. This is obvious: up until now, she had virtually no contact with demons, since she was a normal human girl with normal human girl hobbies, absolutely none of which involved… demons. Kanako-chan had _talked_ about summoning a demon once, but Yuki was reasonably certain it was just an attempt to make her ex-boyfriend nervous, and in the end they’d gotten back together and no actual attempts at contacting hell had happened, as fast as Yuki was aware.

“I’m gonna make a pact with you,” Mammon says. And then, a little louder, as though he’s trying to convince someone: “Yeah! I’m gonna make a pact with you!”

“Yes,” Yuki says, encouragingly, because that’s what she was aiming for… Probably. She’s letting things happen without too much fuss, at this point, because really, when you’re “accepted” (read: forcibly dragged) into an exchange program at a school in what is -- possibly only metaphorically -- hell, what can you do but sit back and watch everything unfold?

“Yeah,” Mammon says. “Yeah.” His voice trails off a little. He looks at Yuki, slowly turning red enough that the tips of his ears turn pink. “So -- here!” 

The pact appears. It’s a seal in the air, that splits into two identical seals and slams into both of them. Yuki keeps herself from flinching, which turns out to be a good idea when it doesn’t hurt at all; it just piffs through her uniform and settles over her heart, sinking into her skin. She can’t see it, but she can feel it inside of her, which is an interesting sensation, to say the least. 

Yuki is suddenly extremely aware that her nose is visible in the center of her vision. 

“Okay,” Mammon says. He puffs his chest out, like he’s just finished winning a marathon. “That’s my part done, so you can just come find me when you’re ready to go! Okay! Bye!” 

Then he’s gone. 

Yuki watches him go and wonders what exactly he meant by “ready to go”.

-

“You made a pact with Mammon?” Solomon says, surprised. He looks Yuki up and down -- not like he’s checking her out, but like he’s seeing her in a new light, appraising her. “That was… fast.”

Yuki blinks. She’s found, in her life, that the best way to get more information is to simply let the person keep talking and not bother to ask any questions. You can find a lot out, that way.

Solomon considers Yuki in silence for a long moment. “Did Mammon tell you how pacts work?”

“Not exactly…” Yuki says.

Solomon heaves a sigh, bringing a hand up to his forehead like blocking out the sight of the classroom will somehow help him manage the situation better. It will not, as Yuki knows from experience.

“A demon makes a pact with you,” Solomon says, and Yuki nods, because she knows that much. “For his part, he just has to say it and it’s binding, but you have to give something over -- traditionally, it’s your soul, but --”

He breaks off as class starts. He offers an apologetic smile as he sits down.

Yuki wonders what exactly she’s gotten herself into, but Solomon exits the classroom too quickly for her to ask.

-

Yuki didn’t expect the explosion that happened when Mammon cheerfully announced he’d made a pact with her. She pauses, fork halfway to her mouth, as five other demons have varying levels of disbelief, ranging from annoyance (Lucifer), dismay (Asmodeus), and unconcerned crunching (Beelzebub).

“You’re an actual idiot,” Satan says, and sips his water.

“I can’t believe you’ve do that! She just _got_ here,” Asmodeus says. “Ahh, I should have moved faster!”

“Gross,” Leviathan says, piling food on his plate to begin the trek back to his bedroom so he won’t have to leave for a solid 16 hours. 

“Mm,” Beelzebub says, upending the entire bowl of mashed darkpotatoes onto his plate. 

“Did you actually _complete_ the pact?” Lucifer asks, deceptively mild in tone.

“Uh,” Mammon says. He turns red again, and Yuki takes the brief lull to finish eating as much as she can, sensing that things are about to go even weirder than usual. 

“You didn’t,” Lucifer says, and the sigh he gives is completely at odds with the way Yuki’s pretty sure she can see his power starting to lance up like fire around him. Mammon scoots his chair a few centimeters away from the table, uncertainly.

“No,” Lucifer says. “Don’t you dare move. You started this, so you have to tell her exactly what is expected of her now.”

“It’s, uh, it’s your soul!” Mammon says, hurriedly.

“Which she can’t give, because that would count as harming her, which you have explicitly been told not to do,” Lucifer says. “Which means?”

“That you can… well, instead, I mean, you can,” Mammon says. He scratches at the side of his cheek. 

“It’s _sex_ ,” Asmodeus says, finally. “You can sleep with a demon to complete forming a pact. It’s one of my favorite ways, in fact, but do you mean that Mammon _hasn’t_ finished forming one with you, in that case?”

“Oh,” Yuki says. “No.” Actually, when she woke up, she could see the imprint of the pact mark on her chest -- it was faint and faded, like a tattoo she’d been given forty years ago and hadn’t maintained at all, but it was there.

“Well,” Lucifer says. “Once you do, the mark will fade unless you’re actively using your pact bond. I imagine that’s important to you and wasn’t said.”

Satan rolls his eyes.

Beelzebub reaches for another plate.

-

Yuki goes to Mammon’s room. He flings open the door, sees who is it, and immediately starts to close it without even acknowledging her. She sticks her foot in the way, and he gives it up as a lost battle before he’s even really started the fight.

“Are you here to yell at me too? Lucifer went on for _ages_ ,” Mammon says despondently, letting his head fall as he steps aside to let Yuki in.

Yuki starts to unbutton her cardigan.

“I know I didn’t warn ya, but it wasn’t like I was tryin’ to _hide_ it,” Mammon says, clicking the door shut.

Yuki folds her cardigan, and then slips off her shoes, placing them both on a pile on the back of the couch before starting in on her button-down shirt.

“I mean, you don’t have to finish the pact or anything if you don’t want to, so it’s not like-- _What are you doing._ ”

Yuki finishes removing her shirt, folds it, adds it to the pile, and then looks at Mammon while she raises her hands to the zipper of her skirt.

“Finishing the pact,” she says, like it’s the most obvious thing in the world. 

Mammon short-circuits. Visibly. She can see him trying to process the situation and _absolutely failing_ , before he dives forward, grabs her cardigan, and wraps it around her.

Her skirt falls to the ground.

“You ain’t gotta do that!” 

“Well,” Yuki says, pleasantly, “I don’t want to give you my soul.”

Mammon stares at her. Yuki looks back, unwavering, but slightly cold without any of the layers of her clothing.

“You really wanna--” Mammon says, then cuts off. He takes a breath. Swallows. Then he smiles, wide and easy. “Yeah, of course you do! Who wouldn’t wanna make a pact with the great Mammon!”

Yuki smiles, patiently, waiting for him to remove the cardigan death trap he’s improvised. He does, after visibly steeling himself; he tosses it onto the couch again, and then stares directly at her chest. She understands; her bra is plain, black, and efficient, because she’s still not sure who actually packed her bags when she became a transfer student. (She thinks it might have been Barbatos, but she hasn’t asked.)

“Wow,” Mammon says, reaching out. He doesn’t quite go for a full on boob touch, which Yuki finds endearing, given that Mammon appears to be more overwhelmed by this than she is. He brushes his fingers across the light pattern of the pact symbol, spread like faded ink on a page across her skin. “It’s like you belong to me! Right?”

Yuki doesn’t answer, because there’s only so far she’s willing to feed into Mammon’s complexes when they’re still in the first week of meeting.

“Yeah,” Mammon says. “I’m cool as _shit_.” 

Then, finally, he leans in to kiss her. 

It isn’t that Yuki has never fucked before: she _has_ , of course, like most of her class. The first time was disappointing, but she’s learned her own techniques since then, and while she isn’t exactly confident on Mammon’s potential performance, being a demon that’s thousands of years old has to count for _something_. She reaches out and grabs his hips and feels him falter in the kiss before he brings his hands up, pulls her closer and kisses her twice as hard to make up for it.

Good, she thinks. 

Mammon seems to gain his bearings as it goes on, for which Yuki is infinitely grateful, but all of his touches still leave way for Yuki to move away, to pull back. She doesn’t, and she isn’t sure how else to convey to him that she has no intention of it -- so rather than try to deal with the subject with words, which have never been her strong suit, she presses against him, walks him backwards towards the couch. 

“Hey,” Mammon says, as the backs of his knees hit the cushions. “Hey, I’m the one that’s gotta--”

He falls backwards, upright against the gunmetal color of the couch cushions, and Yuki carefully lands on top, one knee on either side of him and her hands braced on his shoulders.

Mammon turns red, but he doesn’t protest. He reaches up with purpose -- and then hesitates, redirects to let his hands settle at the curve of her waist, thumbs brushing against the line of her bra.

“Hey,” he says, for the third time in under a minute (not that Yuki was counting). “Are you sure you’re okay with this?”

Yuki tilts her head. It feels a little late in the game to be asking for permission like this; surely it would have gone better in the beginning, when she didn’t understand a pact at all. She toys with the idea of saying no, but she knows she won’t: she’s already here, in Mammon’s room, and in a larger scale, in the Devildom in general. There’s a lot of questions that have been hanging in the air ever since she arrived, and she doesn’t think she’ll find any of the answers she seeks by backing down. The only way out is forward, and the way forward is clear.

Besides; a year of being a transfer student with no hopes of getting laid is a little beyond what she wants to deal with, frankly. Even she had limits. 

“Yes,” Yuki says, finally. “If I didn’t, I wouldn’t have come.”

“Right,” Mammon says. “Right! Yeah, of course.” He offers her a smile -- blindingly bright, and Yuki toys with comparisons to the silver and gold she’s sure Mammon would prefer, but he’s really more like a star -- and then reaches up, letting his hands go for the clasp of her bra.

She leans forward to help him out. She can feel him fumble, and so she rests her head on his shoulder, letting him crane forward to see what he’s doing. He’s careful after the initial removal, reaching up to ghost the bra straps down her arms. She leans back again, and the bra tumbles, catching at her elbows.

Mammon stares, which is fine; her breasts _are_ very nice, and Yuki is proud to say that she grew them herself. His eyes still track her movements as she takes her bra off entirely, setting it as close to the pile of her clothing as she can manage and ignoring the fact that half of it is now on the floor. 

Her underwear matches on a perfunctory level, so frankly, she’s glad to have the bra off, but it does make her realize that she’s hitting overachiever levels in comparison to Mammon, who remains distressingly fully clothed.

Yuki considers her options, very quickly, and then leans back, letting her weight settle precariously on Mammon’s knees.

“Are you going to make me do _all_ the work?” she asks, as sweetly as she possibly can, letting her hand drift up to her chin while her other one drags lightly up the sleeve seam of Mammon’s shirt. She doesn’t quite pout -- she doesn’t have that much faith in her ability to affect a demon with something so dishonest -- but it turns out that she doesn’t need to. 

“Oh, shit!” is all Mammon says before he lifts his arms up, snagging his shirt by the back of the neck to pull it off with an efficacy that would be admirable under any other circumstance. Yuki has seen Mammon shirtless before, given that all of the brothers seem to have a strange penchant for being shirtless as often as possible when in demon form, but she still allows herself a brief moment to take it in.

Demons, she thinks, are unfairly attractive, though she supposes that’s by design, if they’re really out there trying to make pacts by having sex.

“Uh,” Mammon says, hands on his hips as he seems to be caught in a very deep internal debate. “You mind -- I mean, it’s gonna --”

Yuki considers him for a moment, and then, very deliberately, places her palm over his dick. It’s only effective because he’s already aroused, given that she’s doing it through the thick layer of his jeans, but it’s still tremendously effective: he jumps so hard he nearly smacks his forehead into Yuki’s.

She leans back too far trying to get out of the way, and Mammon sweeps an arm around her waist, holding her steady while his own breathing evens out. 

“You gotta warn a guy before you just do somethin’ like that,” he says, and he sounds a little pleading about it. 

“I didn’t warn you?” she asks, and he makes a noise into her shoulder that’s somewhere on the scale of frustrated to aroused. 

“Listen,” Mammon says, and then proceeds not to say anything. Instead, he tightens his grip, and then lifts Yuki up as effortlessly as if she weighed nothing at all. He steps across the room, and she braces herself needlessly by looping an arm around his back so that when he lays her down on his bed, he’s forced to come with her.

Forced is, Yuki thinks, a rather strong sentiment: she can’t force Mammon to do much, yet, with only the echo of the pact sealing them together, but she thinks that’ll change, soon. Not that she really intends on doing very much ordering around, but Mammon doesn’t seem to mind being given orders _that_ much.

Mammon kisses her again, which is nice. Yuki doesn’t need much coaxing to let him take the lead, and Mammon seems to be getting his feet under him -- metaphorically, since they’re both in bed. He brackets his arms around her head as he kisses her, and she wraps her arms around him, letting her fingers drift along the ridges of his shoulderblades and the warm planes of muscle. 

Mammon’s lips move to her neck and Yuki’s hands quest down, along the dip of his hips until they hit the waistband of his pants. She lets her fingers slide underneath, dragging across the skin there, relishing the way that everything is starting to feel superheated and hazy.

Mammon pushes himself up by one hand, letting the other one move down to finally take his pants off. Yuki lets her eyes stick with Mammon’s gaze for a polite amount of time before she looks down as she hears fabric shifting. Mammon’s dick is hard, and about what she’d expect from a demon, given that demons appear to be all the most attractive physical aspects of humanity.

When he reaches down this time, it’s to drag his free hand across her stomach. He moves down with a renewed confidence, his fingers pressing against the crotch of her underwear. She lifts her hips in suggestion, and he smiles against her collarbone, letting her wiggle out of them and then use her foot to fling her panties vaguely in the direction of the couch, probably.

He doesn’t waste much time; he goes directly for her clit, but his touch is light, his fingers gentle. His hands are smooth, and when the first touch makes her buck her hips up, he moves his hand away again, draws circles on the inside of her thigh until he feels her relax.

Mammon presses kisses to her neck, drifts down along her collarbones to her chest. He keeps his hand where it is, dragging slowly from one thigh up to her abdomen and then back down, as he wraps his lips around a nipple. Yuki doesn’t moan, but she does allow herself a sharp intake of breath that borders on a gasp. She’d like to encourage the foreplay, if she can; every touch is like another grain of sand in a sandglass building up to a point that still seems far away.

“Like that,” Mammon says, and when he reaches his hand down again, presses up against her, his fingers move easily against her. He’s prepared when she bucks up again, the feeling still an overwhelming sensation, and he holds her down with a hand across her stomach. She tenses against the weight of his hand, feels the immovable strength of his arm, and then relaxes again.

“Like that,” she agrees, though she doesn’t know which one of them they’re meant to be referring to. It doesn’t matter, and Mammon seems to discard it as unnecessary as well when he slides a finger inside of her.

Almost unconsciously, she spreads her legs a little further. It’s a feeling that slowly takes over all her senses, but at the same time, it isn’t anywhere near enough. Luckily, Mammon seems to feel similarly; he lets his knuckle brush against her clit every time he presses in, but he removes his hand entirely after a moment, slides it across her thigh in a slippery motion before he reaches down to grasp his dick.

Yuki curves her legs up behind his back and reaches out for him, and he obeys the implicit command of the gesture. He presses inside of her in a slow, cautious slide, taking shallow breaths the entire way before he leans down and lets her wrap her arms around him. They kiss, again -- Yuki isn’t really sure if either of them was responsible for starting it, this time, or if they simply met in the middle, both pulled together by the weight of what they were doing -- and Mammon wraps his arm around her again, pulls her into a position that makes it easier for him to slide out and back in, to kick up a rhythm that starts out fast and just goes faster.

“Yes,” Yuki says, curling her fingers into the bedsheet; Mammon doesn’t say anything, which is a small miracle, but he bites down on her shoulder until she gasps. He holds her hips with one hand, disallowing the notion of her own rhythm, and she finds herself incapable of caring when he uses his other hand to keep rubbing against her clit, managing to keep something of a tempo with his thrusts.

“You feel amazing,” Mammon murmurs against her skin, and Yuki groans in response, because sex usually feels amazing but pointing out the obvious doesn’t seem like the best response right now.

“Keep going,” she says, instead. Mammon’s movements get steadily sloppier as he gets faster, and his grip on her hip weakens until she finds herself meeting every thrust, letting out quiet _ah_ noises every time the perfect combination of his hand and his dick spark inside of her. 

The pact isn’t even remotely on her mind. It’s an afterthought; the prologue to a story that she read long before the rest of the book, and everything else is so much more _pressing_ right now. She comes first, which would be surprising if she had the energy to think about it, but she doesn’t: it’s a blinding sky-high moment, suspended with the stars themselves, and she doesn’t think about anything but the nova breaking through her.

She’s aware of Mammon coming, but only peripherally. There’s a second storm blossoming through her, heat ripping outwards from the mark that had appeared on her earlier. There’s a clarity to it, a beautiful sort of understanding that runs through her veins: a whisper of power, of forbidden knowledge, of all the things she’s right on the cusp of knowing.

Then it’s done, and Mammon is done, and they’re both quiet save for their irregular breathing, their lungs trying desperately to regain control over the situation.

“How was it?” Mammon asks, finally. He leans down on his arm and looks at her, carefully angling his weight away from her as he pulls out. “It was great, right? I mean, I’m the great Mammon, after all, so-- hey, stop petting my head!”

Yuki does not stop, but Mammon rapidly stops protesting. Eventually, he reaches his hand up, pressing it down over Yuki’s, and she continues to run her fingers through his hair until he falls asleep, or she does. She isn’t sure which one it is.

-

“O-M-G you really did it!” is the first thing that Yuki overhears as she manages to drag herself down to breakfast. It had been a long trek to wake up early enough to get dressed in last night’s clothing, get to her room, take a shower that was longer than strictly necessary, and then still manage to get up and ready for a full school day.

She was definitely making a pact on a weekend next time.

“Of course I did it!” Mammon is saying as Yuki enters the room. “I’m the great-- there you are!”

Yuki tries to smile, she really does, but her mouth decides to yawn instead, and she brings her hand up to stifle it. By the time she’s done (it was a _really_ good yawn), she’s aware that she has the attention of all six brothers focused directly on her. Well, five brothers; Beelzebub’s attention was still focused entirely on the souffle, which was fair. 

“Good morning,” she offers, and sits down for breakfast, ignoring the way five eyes tracked her every movement.

“Huh,” Satan says.

“Mammon, you _brute_ , you kept her up all night!” Asmodeus says.

“I did _not_!” Mammon objects, immediately.

“You think he’d last that long?” Satan says, his tone deceptively mild, and Mammon makes an enraged noise.

Yuki focuses out, only paying half attention to the brothers as they bicker. Instead, she focuses on the feeling of power that’s fresh in her fingers, the somehow familiar weight of the arcane flowing through her veins.

“Mammon,” she says, very carefully, “be quiet.”

Mammon’s jaw clamps shut, and she smiles.

**Author's Note:**

> you can find me on twitter @warsfeils, where i make bad decisions and play video games and talk about coffee!


End file.
